The present invention relates to cuff electrodes, and more particularly to a curved paddle electrode that may be used with a neurostimulator in order to efficiently apply electrical stimulation to desired nerve fibers or bundles.
A neurostimulator is a device that provides electrical stimulation to selected nerves throughout the body. One type of neurostimulator that has been developed in recent years by Advanced Bionics Corporation of Sylmar, Calif., is a tiny microstimulator known as a BION® microstimulator. Various embodiments and features of such BION microstimulator are disclosed, e.g., in U.S. Pat. Nos. 5,324,316; 5,405,367; 6,051,017, 6,185,452; and in PCT Publications WO 98/43700 and WO 98/43701, each of which patents or publications are incorporated herein by reference.
A microstimulator may be implanted via a small incision and/or via endoscopic means. In one preferred embodiment, the microstimulator is leadless, having electrodes fashioned or formed into its case. In such embodiment, the microstimulator must be implanted next to the nerve or tissue that is to be stimulated. Due to the small size of the microstimulator, such positioning is often possible, and allows desired neurostimulation to occur through minimally invasive surgery.
In other applications, however, it is not possible to implant the microstimulator right next to the nerve or tissue to be stimulated. In such instances, a leaded BION microstimulator of the type shown in applicant's co-pending U.S. patent application Ser. No. 10/188,465, filed 2 Jul. 2002 or U.S. patent application Ser. No. 10/178,011, filed 20 Jun. 2002, may be used. Both of these patent applications are incorporated herein by reference.
When a leaded BION microstimulator is used, an appropriate connection is used to connect the lead to the microstimulator. Such connection may be a detachable connection, as disclosed, e.g., in patent publication U.S. 2002/0193859 A1, also incorporated herein by reference; or a hard-wired connection, as shown, e.g., in the '465 patent application, referenced above.
The manner of connecting a lead to the BION microstimulator, or other neurostimulator, does not form part of the present invention. Rather, the present invention deals with the type of electrode that may be used at the distal end of such neurostimulator lead. The type of electrode used at the distal end of a neurostimulator lead plays a significant role in the effectiveness of the stimulation which is applied through the electrode to the nerve fibers or tissue.
One type of electrode known in the art is a cuff electrode. A cuff electrode encircles a targeted nerve fiber or bundle and offers the advantage of being effectively attached to the target fiber or bundle, thereby preventing the electrode from inadvertently moving away from its desired target. Representative types of cuff electrodes are illustrated in FIGS. 2B, 3A, 3B and 3C of the '465 patent application, previously incorporated herein by reference.
Disadvantageously, cuff electrodes do not always lend themselves to easy attachment to a targeted nerve fiber or bundle. That is, in some instances, the target nerve fiber or bundle, due to its position within the body, is not easily encircled without difficult surgery or without inflicting damage to the surrounding tissue or nerve bundle. For example, sometimes the target nerve bundle is attached along one side to fascia tissue, and there is no way to encircle the nerve bundle without pulling the nerve bundle apart or pulling it away from the fascia tissue. In such instances, there is a need for an electrode that can be attached to the targeted nerve fiber or bundle without encircling it and without inflicting damage to the surrounding tissue.
One type of electrode known in the art is a half-cuff electrode, as shown, e.g., in U.S. Pat. No. 5,344,438, incorporated herein by reference. However, such half-cuff electrode is not adapted to readily fit over a nerve bundle without dislodging the nerve bundle from the fascia tissue to which one side of the nerve bundle is connected. Thus, a need remains in the art for an electrode that can readily fit over a nerve bundle that is attached on one side to surrounding fascia tissue.